Note: Javascript is disabled or is not supported by your browser. For this reason, some items on this page will be unavailable. For more information about this message, please visit this page: About CDC.gov.

Summary Report Hair Analysis Panel Discussion Exploring The State Of The Science

Hair Analysis Panel Discussion: Section 1.1

Historical Document

This Web site is provided by the Agency for Toxic Substances and Disease Registry (ATSDR)
ONLY as an historical reference for the public health community. It is no longer being maintained and the data
it contains may no longer be current and/or accurate.

Section 1
1.1 Background

ATSDR conducts public health assessments to evaluate possible
public health implications of contamination associated with hazardous
waste sites and other environmental releases. An important step
in ATSDR's assessment process is examining exposures to contaminants
under site-specific conditions and determining whether people are
being exposed to contaminants at harmful levels. In most of the
agency's evaluations, the environmental concentration serves as
a surrogate for "exposure."

Exposure concentrations, or estimated doses based on exposure
concentrations, however, represent only one factor in a continuum
of events that ultimately determine whether exposures will result
in illness. Other factors include exposure conditions and various
pharmacokinetic/pharmacodynamic events (e.g., absorption, distribution,
metabolism, excretion), as well as individual variability and susceptibility
in the exposed population. To a large extent, ATSDR evaluates these
factors qualitatively in its public health assessments.

To refine its assessments and/or to fill data gaps, ATSDR seeks
ways to more precisely quantify exposures, such as measuring body
burdens of a particular contaminant or its metabolites (e.g., lead
in blood or arsenic and its metabolites in urine). On a site-by-site
basis, ATSDR evaluates what additional exposure data it might be
practical and useful to obtain to further support public health
evaluations and ultimately to help determine the disease potential
of a particular exposure.

In convening this panel, ATSDR's goal was to determine the overall
utility of hair analysis as one such exposure assessment tool. Hearing
various points of view will help ATSDR draw conclusions based on
the best available science.

ATSDR plans to weigh the information and data presented at the
panel meeting and, in the short term (i.e., over the next several
months), independently develop some interim guidance for its health
assessors and others at ATSDR who are asked by communities about
the virtues of hair analysis in understanding exposures to, or the
disease potential of, particular chemicals. For the purposes of
the panel discussions, ATSDR was not seeking consensus of the panel
on any particular issue, but rather scientific input (consistent
or varied) for consideration by the agency. Also, the panel was
not convened to discuss or evaluate the merits of hair
analysis for other purposes (e.g., testing for drugs of abuse or
nutritional screening). Again, the focus was on environmental exposures.

See the introductory remarks in Section 2
for additional background information.